"The NRL needs to stop in and do something about this," a fired-up Gallen told Channel Nine on Tuesday afternoon.

"The guys that have the ability to go the NFL are the marquee players, they're the best players, they're the players our kids aspire to be like, and he's just broken a contract.

"Not only does he have a Sharks contract, he has an NRL contract.

"The NRL are always on about the integrity of the game, I don't see how this is good for the integrity of the game - a bloke breaking a contract with one year to go and just walking out on a club and the game.

"I think it's gotta be a minimum two years out of the game, if not out forever."

Holmes has scored 66 tries in 105 games with Cronulla, emerging as one of the competition's premier backs.

The 23-year-old was the subject of a big-money contract offer from the Sharks as well as North Queensland.

Gallen says he is most disappointed about the club being left short for 2019 following Holmes' departure.

"That's what I'm most upset about and I've expressed that to Val.

"I'm not saying anything I haven't said to Val, I wish him well as a person, I like Val, he's a great kid and if anyone can make it in the NFL, it'll be him, but the way it's happened.

"If you're off contract, go for your life, do what you want, you're not letting anyone down, but that fact is, he's got one year to run on his contract, he's letting the playing group down, he's letting the club down and he's left us in a big hole.

"You don't get this far in this game, or any game, without your teammates and Val's left us, he's walked out on us, which I find disappointing and I've told him that."

Gallen also took to Twitter to respond the suggestion that him boxing while under contract was a comparable situation.

Let's not throw "if's" around Russ it's stupid, what if I get hit by a car, lightening? 🙄 talk facts as that's all I've done. I don't think leaving the game, your club or teammates with a yr to go on your contract in late November with most players signed for 2019 is right.

Hayne discussed it with the club, decision was made by the the club to let him go end of season. Not dropped late November via media with no discussion or opportunity to plan. If u listen I say if anyone can make it he can (Val) and I hope he does. Again get the facts right champ